CONFIG_MFD_WM831X (not configurable)

modulename: wm831x.ko

configname: CONFIG_MFD_WM831X

Linux Kernel Configuration
└─>Device Drivers
└─>Multifunction device drivers
└─>MFD_WM831X
In linux kernel since version 2.6.32 (release Date: 2009-12-02)  
source code:
drivers/mfd//
depends
CONFIG_GENERIC_HARDIRQS
CONFIG_HAS_IOMEM

is selected by
CONFIG_WM831X_WATCHDOG